An optical image can be described by its intensity distribution on the image plane. It is usually written as a function of the horizontal X-coordinate and the vertical y-coordinate. However, it can also be described by the radial distance, R, from the origin and the corresponding angle, .theta., between the radius line and the horizontal x-axis. These two sets of parameters are the rectangular coordinates x, y and the polar coordinates R, .theta., respectively, as shown in FIG. 1. In image analysis and many image processing systems, it is frequently desired to produce a remapped image. For example, in converting an image from the rectangular to polar coordinate system, the remapped image is laid out on a rectangular coordinate system U, V, with U equal to R and V a function of .theta. in the original image. Thus, for example, a circle in the polar coordinate system as shown in FIG. 2A would be remapped into a vertical line in the U, V image, as shown in FIG. 2B. Mathematically, this remapping transform is described ##EQU1##
However, due to the amount of calculation required for each point, such remapping in the past had to be done by a computer, if the remapping was to be done with any reasonable speed. Thus, either a specially built video processor which transforms digitized images in real-time or a computer with a frame grabber that processes one image frame at a time in nonreal-time was required.